String Handling in Formula Compiler

Compiling formulas almost unconditionally calls toUpper() on every token parsed and spends way too much time in the underlying i18n routines.

No need to do this at all for tokens of operators, separators, parentheses, ... all tokens that do not involve letters.

When loading ODF documents, only a simplified ASCII toUpper() needs to be called, since all function names are stored using English names.

A test case document is attached to Issue 99828 , containing two columns of functions, 64k rows of formulas each, with a function name, some references, a value and a few operators and separators. Profiling gave